Photographic aperture regulating device



Jan. 3, 1967 H. NERWlN PHOTOGRAPHIC APERTURE REGULATING DEVICE FiledJan. 10, 1964 LIGHT 27 I N] Is N] l SENS/N6 -26 CIRCUIT FIG.

28 L/GHT s N S N SENS/N6 26 CIRCUIT FIG 2 llllllll 2 Sheets-Sheet 1HUBERT NERw/ INVENTOR.

Jan. 3, 1967 H. NERWIN 3,295,428

PHOTOGRAPHIG APERTURE REGULATING DEVICE Filed Jan. 10, 1964 2Sheets-Sheet 2 mzzrzz mzsszaa F/G 5 25 AIM FIG 7 LI GHT SE 5 HUBERTNERW/N INVENTOR. CIRCUIT ATTORNEY United States Patent 3,295,428PHOTOGRAPHIC APERTURE REGULA'IING DEVICE Hubert Nerwin,'Rochester, N.Y.,assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of NewJersey Filed Jan. 10, 1964, Ser. No. 337,032 8 Claims. (CI. 95-64) Thisinvention relates to a device for regulating the effective size of aphotographic aperture, and more particularly to an adjustable diaphragmvane device and method of making such a vane device that is positionablein accordance with interaction between permanent magnet means andsolenoid means variably energized as a function of sensed illumination.

It is an object of this invention to regulate the effective size of aphotographic aperture by means of a simple device that iselectromagnetically positionable.

Another object of the invention is to reduce the manufacturing costs ofa photographic aperture regulating device.

Another object of the invention is to form a diaphragm vane means from asingle piece of material.

Another object of the invention is to eliminate the effects ofhysteresis on an electromagnetic diaphragm vane adjusting mechanism.

Another object of the invention is to position a diaphragm vane by meansof an electromagnetic actuator that is non-linear in its response tosensed illumination.

Another object of the invention is to regulate the effective size of adiaphragm aperture by means of a device that is reliable and accurate inoperation, and to make such a device by a method that is simple andeconomical.

Another object of the invention is to eliminate the multiplicity ofparts and reduce the relative movements of parts forming a diaphragmaperture size adjusting device.

These and other objects of the invention are accomplished by formingfrom a piece of bendable material an elongated member havinglongitudinally spaced notched vanes arranged so that when the member isbent into a U-shape, the notched vanes overlap and form an adjustableaperture the effective size of which varies as a function of the overlapof the vanes. Such a U-shaped or equivalent diaphragm vane device ispositioned by the magnetic repulsion between solenoid or coil meansvariably energized as a function of sensed illumination and permanentmagnet means, no other magnetic material being present within theeffective magnetic field of the solenoid means. The invention will bemore clearly understood by reference to the following description andthe accompanying drawings wherein:

FIGS. 1 and 2 show partially schematic, partially sectioned front planviews of a diaphragm aperture adjusting device according to theinvention.

FIG. 3 shows a partially schematic, partially sectioned side view of thedevice of FIGS. 1 and 2.

FIGS. 4 and 5 show steps in the method of fabricating the diaphragm vaneillustrated in FIGS. 13.

FIG. 6 shows a plan view of an alternate vane configuration suitable fora single piece diaphragm vane device.

FIG. 7 shows a partially schematic, partially sectioned front plan viewof a two vane diaphragm aperture adjusting device according to theinvention.

As shown in FIGS. 1-3, a U-shaped diaphragm vane member 10 has legportions 11 and 12 integral with vanes 13 and 14 that have respectivenotches 15 and 16 for regulating the effective size of photographicaperture 17 as a function of the overlap of the vanes. The overlap ofthe vanes 13 and 14 is in turn regulated by the position of leg portions11 and 12 of U-shaped member 10. U-shaped member 10 is supported in aholder 18 having an adjusting screw 19 for calibrating the overlaps ofvanes 13 and 14.

To incorporate the aperture adjusting member 10 into a photographiccamera, holder 18 is fixed to the camera so as to position notches 15and 16 over a camera taking lens aperture 17 for varying its effectivesize. To facilitate such an arrangement, camera taking lenses 20-22 canbe associated with aperture 17 as shown in FIG. 3.

For positioning vanes 13 and 14 so as to regulate the effective size ofaperture 17, a coil or solenoid 23 is in circuit with schematicallyillustrated light-sensing circuit 24 so that solenoid 23 is variablyenergized as a function of sensed illumination. Many well-knownphotocell circuits including unassisted selenium cells, photoconductivecells with batteries, and amplified photocell outputs may be used aslight-sensing circuit 24. Typically such photocells are arranged foraccepting illumination from a scene to be photographed.

Interacting with the variable field of solenoid 23 are two permanentmagnets 25 and 26 fixed respectively to arms 27 and 28 so as to extendinto the hollow center of solenoid 23 as shown in FIG. 1 wheneversolenoid 23 is unenergized. Diaphragm adjusting member 10 including legs'11 and 12 and arms 27 and 28 is prefer ably formed of nonmagneticmaterial so as not to be aifected by the magnetic field of solenoid 23.Magnetic material within the effective variable field of solenoid 23such as soft iron that is subject to the effects of hysteresis wouldintroduce inaccuracies into the functioning of diaphragm aperture vanes13 and 14. In other words, such magnetic material would retain someresidual magnetism after a cycle of operation of coil 23 depending onprevious induced magnetism and thus would start each aperture regulatingcycle with variable and unknown conditions of induced magnetism. Thisresults in inaccuracies in the positioning of vanes in response to theenergization of coil 23. By eliminating from the effective magneticfield of solenoid 23 all magnetic ma terial other than permanent magnets25 and 26, the errors produced by hysteresis are eliminated. Permanentmagnets 25 and 26 retain their fixed values of induced magnetism so asnot to be subject to any variation from hysteresis effect. Once theinaccuracies from variable magnetic reactions from hysteresis areeliminated, a simple device such as illustrated in FIGS. 13 can functionaccurately to regulate the effective size of aperture 17 as a functionof the illumination sensed by lightsensing circuit 24.

The interaction between the variable magnetic field of solenoid 23 andpermanent magnets 25 and 26 is one of magnetic repulsion. This has theadvantage of positioning vanes 13 and 14, as a function of a non-linearresponse to sensed illumination. Since the magnetic field strengthwithin the hollow core of solenoid 23 for any given value ofenergization is uniform from the center to the edges of the coil, and isstrongest throughout such a zone, magnets 25 and 26 react to thegreatest repulsive forces available for the lower values of illuminationand to relatively decreased repulsive forces for increases inillumination from higher values of light intensity. Thus, when sensedillumination is at low values, magnets 25 and 26 are relatively stronglyrepulsed toward the ends of coil 23 and for intense illumination andrelatively high energization levels of solenoid 23, magnets 25 and 26begin to withdraw from the ends of coil 23 and increased illuminationproduces relatively weaker increases in repulsive forces. This isdesirable for approximating the log-linear conversion of sensed lightintensity to mechanical movement.

Of course, the relative positions of solenoid and permanent magnetscould be interchanged. Thus, two hollow solenoids could move over theends of a fixed permanent magnet. Also, solenoid 23 could be formed intwo connected coils and arms 27 and 28 could be located in anotherposition, for example, bent outwardly of legs 11 and 12 for interactingwith separate solenoid coils. Alternatively, the solenoid could be fixedto one leg of member and a permanent magnet fixed to the other leg.

In FIG. 7 is illustrated an alternative embodiment of the inventionusing two pivoted diaphragm vanes 30 and 31 having respective falcate orsickle-shaped openings 32 and 33 co-operating to define photographicaperture 17 that is variable as a function of the overlap of vanes 30and 31. Vanes 30 and 31 are mounted for rotation about pivot points 34and 35 respectively. Respective springs 36 and 37 operate to returnvanes 30 and 31 from any deflected position to the position illustratedin FIG. 7 in which the vane openings 32 and 33 provide maximum eifectivesize for aperture 17. Permanent magnets 25 and 26, fixed respectively tovanes 30 and 31, interact repulsively with coil 23, and light sensingcircuit 24 variably energizes coil 23both as described above for FIGS.1-3.

One advantage of the diaphragm aperture adjusting member 10 illustratedin FIGS. 1-3 is that it can be manufactured from a single piece ofmaterial by an advantageous method, steps of which are illustrated inFIGS. 4-6. A piece of bendable and preferably non-magnetic materialshould be selected, suitable materials including non-magnetic metalssuch as aluminum and various plas tics. To make the diaphragm vanemember 10 illustrated in FIGS. 1-3, the elongated member 10 illustratedin FIG. 4 is cut from a flat piece of bendable material. Such member hasleg portions 11 and 12 and vanes 13 and 14 having respectivenotches and16. Arms 27 and 28 also extend from leg portions 12 and 11 respectively.Although arms 27 and 28, and vanes 13 and 14 may extend from either oralternate sides of member 10, it is preferred that vanes 13 and 14extend from the same lateral side of elongated member 10 as illustratedin FIG. 4.

Alternatively, vane 40 having notch 41 as illustrated in FIG. 6 may besubstituted for the vane configuration of vanes 13 and 14 as illustratedin FIGS. 4 and 5.

Right angle bends are formed at dotted lines 42-45 or 46 that arelocated where vanes and arms project laterally from elongated member 10.Such right angle bends are made so that vanes 13 and 14 extend from thesame face of leg portions 12 and 11 respectively as illustrated in FIG.5. In such position vanes 13 and 14 are coplanar in a plane normal tothe plane of leg portions 11 and 12. Arms 27 and 28 are similarly bentat right angles so as to project from the same face of leg portions 11and 12, but, as indicated above, arms 27 and 28 could be bent inopposite right angles so that either one or both of arms 27 and 28extended in -a direction 180 rotational degrees from the directionillustrated in FIG. 5. The determining factor for the bends of arms 27and 28 is the desired location and number of solenoids or permanentmagnets.

When the member, 10 formed as illustrated in FIG. 5, is bent into aU-shape as illustrated in FIGS. 1-3, vanes 13 .and 14 overlap to definethe effective size of aperture 17. With the fixing of permanent magnets25 and 26 to arms 27 and 28 respectively, diaphragm aperture adjustingmember 10 is ready for insertion into holder 18. Adjustment of screw 19calibrates member 10 for operation.

The advantages of the above-described vane manufacturing method includesimplicity, economy of parts, elimination of assembly operations, andreduction of the possibilities for manufacturing errors, all of whichcontribute to economy of manufacture.

The invention has been described in detail with particular reference topreferred embodiments thereof but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention as described hereinabove and as defined in the appendedclaims.

I claim:

1. A device for regulating the effective size of a photographic apertureas va function of the illumination of a photoresponsive element,comprising: movable adjusting means the position of which determines theeffective size of said aperture; and a solenoid actuator comprisinghollow coil means and permanent magnet core means movable relative toone another and one of which is movable with said adjusting means, saidcoil means being in circuit with said photoresponsive element andvariably energized as a function of said illumination, and said coilmeans and said permanent magnet means being relatively arranged so thatwhenever said coil means is unenergized, said permanent magnet meansextends into the hollow of said coil means, and whenever said coil meansis energized, said coil means and said permanent magnet means are urgedapart so as to position said adjusting means as a function of thestrength of the magnets field of said coil means, said permanent magnetcore means being adapted to be at least partially withdrawn from saidhollow coil means when said aperture is at its smallest size.

2. The device of claim 1 wherein said adjusting means comprises apivotally mounted vane having a falcate opening therein.

3. The device of claim 1 wherein the portions of said adjusting meansarranged in the vicinity of said coil means are formed of nonmagneticmaterial.

4. A device for regulating the effective size of a photographic apertureas a function of the illumination of a photoresponsive element,comprising: a coil in circuit with said photoresponsive element andvariably energized as a function of said illumination; a U-shaped,resilient, aperture-size-adjusting member having notched vanes integralwith each leg of said member, said vanes partially overlapping eachother so that their respective notches cooperate to define an aperturethat is variable in size in response to the relative positions of thelegs of said U- shaped member; and two permanent magnets, each one ofwhich is fixed to a respective leg of said U-shaped member, said magnetsbeing arranged for moving away from the coil in response to the increasein magnetic field of said coil for positioning the legs of said U-shapedmember as a function of the strength of the magnetic field of said coil,said permanent magnets being adapted to be at least partially remotefrom said coil when said aperture is at its smallest size.

5. The device of claim 4 wherein said U-shaped member is formed ofnon-magnetic material.

6. The device of claim'4 wherein said coil is hollow and said magnetsextend into said coil whenever the latter is unenergized.

7. A device for regulating the effective size of a photographic apertureas a function of the illumination of a photoresponsive element,comprising: solenoid means in circuit with said photoresponsive elementand variably energized as a function of said illumination; a pair ofpivotally mounted diaphragm vanes having respective falcate openingsthat co-operate to vary the size of said aperture as a function of therotational positions of said vanes; and two permanent magnets, eachfixed to a respective 5 6 one of said vanes, said magnets being arrangedfor mov- References Cited by the Examiner ing away from said solenoidmeans in response to the increase in strength of the magnetic field ofsaid solenoid UNITED STATES PATENTS means for positioning said vanes,said magnets being 2,206,086 7/ 1940 Galyon 9564 adapted to be at leastpartially remote from said solenoid 5 2,973,699 3/ 1961 Nerwin 95-64means when said'aperture is at its smallest size. 3,032, 74 3 19 3 Bagby5 8. The device of claim 7 wherein said solenoid means comprises ahollow coil, and said permanent magnets NORTON ANSHER Primary Examinerextend into opposite ends of said coil Whenever the latter isunenergized. 10 CLIFFORD B. PRICE, Assistant Examiner.

1. A DEVICE FOR REGULATING THE EFFECTIVE SIZE OF A PHOTOGRAPHIC APERTUREAS A FUNCTION OF THE ILLUMINATION OF A PHOTORESPONSIVE ELEMENT,COMPRISING: MOVABLE ADJUSTING MEANS THE POSITION OF WHICH DETERMINES THEEFFECTIVE SIZE OF SAID APERTURE; AND A SOLENOID ACTUATOR COMPRISINGHOLLOW COIL MEANS AND PERMANENT MAGNET CORE MEANS MOVABLE RELATIVE TOONE ANOTHER AND ONE OF WHICH IS MOVABLE WITH SAID ADJUSTING MEANS, SAIDCOIL MEANS BEING IN CIRCUIT WITH SAID PHOTORESPONSIVE ELEMENT ANDVARIABLY ENERGIZED AS A FUNCTION OF SAID ILLUMINATION, AND SAID COILMEANS AND SAID PERMANENT MAGNET MEANS BEING RELATIVELY ARRANGED SO THATWHENEVER SAID COIL MEANS IS UNENERGIZED, SAID PERMANENT MAGNET MEANSEXTENDS INTO THE HOLLOW OF SAID COIL MEANS, AND WHENEVER SAID COIL MEANSIS ENERGIZED, SAID COIL MEANS AND SAID PERMANENT MAGNET MEANS ARE URGEDAPART SO AS TO POSITION SAID ADJUSTING MEANS AS A FUNCTION OF THESTRENGTH OF THE MAGNETS FIELD OF SAID COIL MEANS, SAID PERMANENT MAGNETCORE MEANS BEING ADAPTED TO BE AT LEAST PARTIALLY WITHDRAWN FROM SAIDHOLLOW COIL MEANS WHEN SAID APERTURE IS AT ITS SMALLEST SIZE.